Sources of folate: where can we find folate in food?

Our bodies are unable to produce folate, which is why we need to get a supply of this vitamin through the foods we consume. The best way to do that is by regularly eating foods that contain naturally occurring folate, such as legumes (beans, nuts, peas, etc.), dark leafy greens (e.g., spinach, romaine lettuce), vegetables (asparagus, broccoli, cauliflower) and (fermented) dairy products – or alternatively, by consuming some products that are fortified with synthetic folic acid (e.g., flour, bread, pasta, breakfast cereals, fruit and vegetable juices), or by taking dietary supplements (Iyer and Tomar, 2009;Bassett and Sammán, 2010; Homayouni, 2016).

To prevent folate deficiency and potential health problems – like (megaloblastic) anemia, neural tube defects, cancer, neurocognitive decline or depression – the recommended intake should be at least 400 μg/day for adults and 600 μg/day for pregnant women (SCAN, 2006).

In order to reach the recommended daily value of folate you might consider taking dietary supplements that contain synthetic folic acid or the bioactive form of folate, methyl folate, also so found in Quatrefolic^®.

 

Folate and eggs

Eggs are considered a super-food because of their high content in macro and micronutrients such as high-quality proteins, vitamins and lipids – including polyunsaturated fatty acids (PUFA) and phospholipids. In fact, eggs are not only rich in naturally-occurring folate derivatives, but they also contain vitamin A, iron, vitamin B12, riboflavin, choline, as well as zinc and calcium (Drewnowski, 2010). 

One egg (60 g) can provide between 40–86 µg of folate, which corresponds to 10–22% of the DRI for adults. 

The yolk is the main source of folate found in eggs, ranging from 63.5 µg/100 g in free range eggs to 143 µg/100 g in organic eggs. Most of the folate found in eggs is 5-methyltetrahydrofolate (methylfolate), which is known as the metabolically active form of folate that can be readily absorbed by the body (Seyoum and Selhub, 1998), just like folate found in Quatrefolic^®.

Eggs also have greater folate stability compared to plant-derived food. The higher content of antioxidants, in particular cysteine (Seyoum and Selhub, 1998), found in eggs may result in greater folate retention after steaming, grilling or ‘sous-vide’ cooking (Czarnowska-Kujawska et al., 2020). 

When comparing raw and cooked egg yolks, the results have shown that folate retention further increases, even by 97%, when eggs are fried and/or boiled (Bassett and Sammán, 2010).  

Folate and vegetables

Vegetables are an excellent source of folate and are also rich in fiber, vitamins and minerals. Vegetables which contain the highest content of folate are green and yellow beans, peas, cauliflower, broccoli and spinach. Folate in vegetables is also present in the biologically active form, known as 5-methyltetrahydrofolate (methylfolate) (Czarnowska and Gujska, 2012), which is also found in Quatrefolic^®.

Folate concentrations (μg folate in 100g of dry/raw form) can vary between vegetables, ranging from 142 μg in peas and 147 μg in lentils, to 169 μg in beans and even 275 μg in chickpeas. 

Other high-folate vegetables include spinach (165 μg folate/100g), turnip (124 μg folate/100g), Chinese cabbage (114 μg folate/100 g), cabbage (66 μg folate/100 g) and cauliflower (17 μg folate/100 g).  

Here is a detailed list of folate-rich vegetables (% DV) based on a recommended serving size: 

• Edamame – 482 μg folate (121% DV) in one cup, cooked; 
• Lentils – 358 μg folate (90% DV) in one cup, cooked; 
• Chickpeas – 282.1 μg folate (71% DV) in one cup, cooked; 
• Spinach – 263 μg folate (66% DV) in one cup, cooked; 
• Kidney Beans – 230.1 μg folate (58% DV) in one cup, cooked; 
• Broad Beans (Fava) – 176.8 μg folate (44% DV) in one cup, cooked; 
• Broccoli – 168 μg folate (42% DV) in one cup, cooked; 
• Raw Beets – 148.2 μg folate (37% DV) in one cup; 
• Brussels Sprouts – 93.6 μg folate (23% DV) in one cup, cooked; 
• Kale – 84.5 μg folate (21% DV) in one cup, chopped & cooked. 

Cooking vegetables can significantly reduce folate content. For example, heat can considerably reduce folate content by about 50–80% for boiled green vegetables and legumes, compared to raw vegetables (McNulty and Pentieva, 2004). Similarly, soaking (Xue et al., 2011) can result in lower folate content in pulses, probably due to folate leaching into the soaking water. 

On the other hand, food processing such as chopping may have the opposite effect and increase folate bioavailability from leafy vegetables. For instance, chopped spinach has higher folate bioavailability than folate from whole spinach leaves, assuming equal portions are used in both cases (McNulty and Pentieva, 2004).  

It is also interesting to nte that the process of lactic fermentation can increase folate content in fermented vegetables, depending on the bacteria used (Jägerstad et al., 2004).

Folate and fruits

In the fruit category, tropical fruits such as guava, mango, melon or pineapple appear to have higher folate content, whereas others like peach or apple contain lower levels of folate.  

For example, a portion of 110 g of passion fruit is considered enough to cover the recommended daily intake of 300 µg of folate for adults (Krawinkel i wsp., 2014). 

Here is a detailed list of folate-rich fruits (%DV) based on an recommended serving size: 

• Avocados – 163 μg folate (41% DV) in one medium-size avocado; 
• Guavas – 80.9 μg folate (20% DV) in one cup; 
• Mangos – 71 μg folate (18% DV) in one cup (pieces); 
• Oranges – 54 μg folate (14% DV) in one cup (sections); 
• Strawberries – 39.8 μg folate (10% DV) in one cup, sliced; 
• Cantaloupe Melon – 37.2 μg folate (9% DV) in one cup (balls); 
• Passion fruit – 33 μg folate (8% DV) in one cup; 
• Pineapple – 29.7 μg folate (7% DV) in one cup (chunks); 
• Bananas – 23.6 μg folate (6% DV) in one medium-size banana; 
• Raspberries – 25.8 μg folate (6% DV) in one cup;  
• Clementines – 17.8 μg folate (4% DV) in one clementine; 
• Apple – 4 μg folate (1% DV) in one medium-size apple; 
• Peach – 2.94 μg folate (0.74 % DV) in one medium-size peach. 

Folate-boosting food combinations

In order to efficiently boost your folate intake throughout the day, we have prepared for you some recipes that are high in folate, which you can eat for breakfast, lunch or dinner.  The following food combos will not only increase your folate intake, but at the same time provide your body with many health-promoting nutrients, to keep your energy levels high all day long and help you feel fuller for longer.  

• Poached eggs and avocado on toast 
• Chickpea salad with spinach and lentils 
• Bean, pea and green lentil salad 
• Avocado, pumpkin/sunflower seeds and spinach salad 
• Roasted asparagus with scrambled eggs 
• Cauliflower and chickpea curry 
• Mango avocado salsa 
• Green smoothie: mix of avocado, mango and spinach 

What affects folate levels in foods?

Naturally-occurring folates found in plant- and animal-based foods are very sensitive to cooking/preparation and storage. High temperature, exposure to sunlight or long storage can lead to folate deterioration, and therefore reduce folate content in foods (Bassett and Sammán, 2010). 

Cooking methods – soaking, boiling, steaming, thawing, roasting, frying, microwave heating and homogenization – have a significant impact on folate content found in plant-based products (Czarnowska and Gujska, 2012). 

For example, the highest folate losses were observed after canning, where 65% and 77% of folate were lost in spinach and chickpeas, respectively. Boiling and blanching also strongly affect folate concentrations, reducing folate content by 25% for boiled green peas and by 70% for cooked chickpeas. But the highest losses caused by blanching were found in spinach, with an average ranging between 50% to 95%. It is also worth noting that no significant folate losses were observed after steaming or microwave heating (Bureau et al., 2015). 

Canning and freezing are storage methods that can significantly decrease folate content in vegetables, in particular pre-cut vegetables (chopped spinach) and very small products (green peas). For example, cauliflower that has been frozen for three months can lose 95% of its methylfolate content compared to fresh cauliflower (Czarnowska and Gujska, 2012).